FULL-SCALE FEASIBILITY OF THE Forward Osmosis-MBR PROCESS FOR WASTEWATER RECLAMATION

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FULL-SCALE FEASIBILITY OF THE FO-MBR PROCESS FOR WASTEWATER RECLAMATION

M. Arnaldos, T. de la Torre, C. Rodríguez and J.J. MalfeitoOZWATER 2015, Adelaide (Australia)

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Index

1. Introduction and Objectives

2. Materials and Methods

3. Results and Discussion

• DS Selection

• Long-term FO-MBR Operation

• Preliminary Cost Evaluation

4. Conclusions

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FO technology has been receiving increased attention in the last years A wide variety of organizations are developing technological solutions for FO

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Improvements in FO membranes: higher fluxes and increased performance

Increase in number of membrane providers: decrease in costs

Introduction: FO-MBR

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Introduction: The FO-MBR Technology

Forward Osmosis Membrane Bioreactor (FO-MBR)

(Coday, 2014)

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No need for membrane cleaning and scouringLower energy consumption

Reversible foulingConstant operational cost through time

High removal efficienciesEmerging contaminantsBoron

FO-MBR and DS recovery system = multibarrier treatment systemPotential for potable reuse?

Production of reclaimed water for different usesE.g. fertigation

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Introduction: FO-MBR Potential

(Mi and Elimelech, 2009)

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Introduction: FO-MBR Challenges

Internal Concentration Polarization (ICP)Reduced Water FluxesSalt Concentration in Bioreactor

Draw Solution Selection and SeparationIncreased Operational Cost

Emerging TechnologyFeasibility Assessment

(Productivity, Energy Requirements, Fouling Occurrence)

(Achilli et al., 2010)

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Optimization of FO-MBR Operational ConditionsSelection of Promising DS Through Mathematical ModelingDifferent Compositions and Concentrations of Draw

Solution (DS): Water Flux, ICP, Salt Accumulation in Bioreactor

Assess Long-Term Feasibility of FO-MBR for Activated Sludge Treatment at Lab ScaleExperimental Process EvaluationProcess Efficiency, Water Fluxes, Reverse Salt Transport,

Membrane Fouling

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Research Objectives

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Materials and MethodsSelection of a Promising DS through Mathematical Modelling

J wC+J s=D effdCdx

Intrinsic properties of DSs:- Van’t Hoff

Coefficient (β)- Diffusion Coefficient

(D)

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Materials and MethodsExperimental Process Evaluation

FO-MBR Pilot Plant

• Feed: 4L/min, 1 bar; DS: 1L/min, 0.5 bar.• Continuous Operation (1 month/DS)• Real Activated Sludge from MBR Biological

Reactor

Membrane test cell (CTA, HTI)

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Flux

β

D

π

I.C.P.

Results and Discussion

Selection of a Promising DS through Mathematical Modelling

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Results and Discussion

Selection of a Promising DS through Mathematical Modelling

• List of highly soluble inorganic and organic (>2 M) salts

• Discard salts with ions regulated by reclamation legislation

• Discard hazardous substances

• Select a group with high D & β coefficients

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Results and Discussion

Selection of a Promising DS through Mathematical Modelling

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Results and Discussion

K4P2O7 HCOOK

Experimental Process Evaluation

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Preliminary Cost Comparison

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- Comparison based on cost of replacement for 6 LMH

- Other operational costs would remain equal

- Replacement is due to reverse salt flux and RO effluent concentration

Potassium Pyrophosphate is approximately 44% cheaper from an operational perspective

(Achilli et al., 2010)

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Main ConclusionsFO-MBR is an emerging low fouling technology

Long-term operation without fouling was demonstrated

Reducing replenishment costs of DSs is an important challenge

Further search for DSs together with membrane advances is required for full-scale feasibility

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Industrial Waters• Requiring high quality and complex treatment• With fouling problems (requiring extensive pretreatment)• Applications with no DS separation

Municipal Waters for ReusePotable• Indirect• Direct (Singapur/Namibia…)

Irrigation• Boron• Microcontaminants• High TDS• Heavy metals

Opportunities

Industrial• Cooling towers• Residual heat

Case-by-case analysis in order to determine appropriateness of FO solution!

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AcknowledgementsWe would like to thank ESAMUR and Aguas y Servicios de la Costa Tropical for their collaboration.The research leading to these results has received funding from:• LIFE+ Programme of the European Commision (LIFE12/ENV/ES/000632

LIFE OFREA) www.life-ofrea.com

• People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2015 under REA agreement 289193 (SANITAS Project).

This presentation reflects only the author's views and the European Union is not liable for any use that may be made of the information contained therein.

I+D+iI+D+i © 2015 Acciona Agua S.A.U. All rights reserved.